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Unstable Burning In Solid Propellants ± Fame But No Fortune

M. Richard Denison

This Presentation Is About A Paper That I Wrote With Eric Baum Which Was Published In 1961
I will discuss:  The unusual way it came into being  A brief summary of its contents  Background and importance of the problem  Community response in first 10 years  Lessons learned Much of the material presented was compiled by Dr. Baum

David Altman
 Dr. Altman retired as senior vice president of United Technologies in 1981 after 23 years  He spent two and a half years at University of California Radiation Laboratory (Manhattan Project)  For eleven years he was Chief Chemist at JPL  At Aeronutronic he was director of the Vehicle Technology Laboratory
.My Boss At Aeronutronic Was Dr.

My Introduction To The Problem
Several times I was present in Dave¶s office when he brought up the important problem of solid propellant combustion instability He usually had some famous physicists and other visitors in his office when he discussed the problem Nobody had a good idea about what controlled the phenomenon I thought I had a good idea ± the transient behavior must be controlled by the solid because its density was much greater than that of the gas
.

How Our Work Got Started
In addition to being a brilliant scientist Dave was a terrific salesman . and that is how this work came into being
.We had lots of projects One day as I was walking to my office one of Dave¶s project managers stopped me and told me about an unusual problem ± his contract was almost over but he did not have any way to spend the money He asked if I had any ideas I told him I did.

no reactions in solid state.The Model
 Time lags in the gas phase neglected while transient
conduction in the solid takes place  Results obtained by a perturbation of laminar flame conditions and transient heat conduction in the solid  Burning rate and heat flux developed from conservation equations  Assumptions include homogeneous propellant. single step reaction of any order. and no erosive burning  Because resulting equations are linear a Laplace transform method of solution was used ± results are analytic
. Lewis number of unity. vaporization according to an Arrhenius law.

Organization Of The Combustion Instability Research Effort
 (1958)Polaris Program Mgrs. McClure (APL) Assigned To Coordinate Effort As Head Of What Was The Forerunner Of The JANNAF Combustion Subcommittee
. ARO & ARPA)  F. & DOD Committee On Large Motors Recommend Setting Up Ad Hoc Committee That Then Recommends An Enhanced Coordinated Research Program To Be Implemented By A Tri-service Committee (ONR.T. AFOSR.

 Hart. At APL Were Doing The Best Work At The Time e.g. RW & McClure. Phys 30. J.. FT. . Cantrell.. ³Combustion Instability.PROS/CONS Of Assigning McClure To Run The Top-Level Oversight Committee
 PRO: McClure Was Among The Best & Brightest
± McClure. 1504 (1959)
 CON: There Were Conflicts Of Interest
± APL Continued To Work The Problem For The Navy Internally While The Oversight Committee Judged Both The APL Work And Outside Work Funded By Participating Sponsors ± APL Acted As Technical Director For Navy-Sponsored Work Outside Of APL
. Hart. Acoustic Interaction With A Burning Propellant Surface´. Chem.

Subsequent History
 Hart-McClure is a historical footnote  Denison-Baum is still used (50 yrs later) as basis for models relaxing the approximations or as the limiting case for non-linear models  When I would meet some scientist for the first time I was often asked. ³Are you the Denison of Denison and Baum? I thought you were dead´ ± Fame but no fortune
.

Lessons Learned
 The ³Best And Brightest´ Had Both The Direct And The Top Level Oversight Of The D-B Modeling But Failed To Recognize Its Value Until 5 Years Later  This Is In Part Because Confidence In The Somewhat Arcane Mathematics Grows With Each Successful Subsequent Application  Perhaps More Effort Would Have Been Put Into Understanding The Model If APL Had Not Been So Confident That They Had The Modeling Well In Hand  We Never Could Have Done This Work At All If We Had To Write A Proposal
.